Fabrication of welded wheels without filler material

ABSTRACT

A hermetically sealed wheel assembly which has been welding autogenously is provided, along with a method and system for welding the wheel assembly. The wheel assembly is made up of at least two components which are laser welded to each other without the use of filler material to create a hermetically sealed wheel assembly.

PRIORITY

The present application is a continuation of U.S. patent applicationSer. No. 13/269,319 which is incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates to the art of welding and moreparticularly to the fabrication of welded wheels without fillermaterials.

BACKGROUND OF INVENTION

As the art of arc welding has grown, it has found its application inmany different structures and uses. It is known that although arcwelding can provide a strong bond between metallic components, dependingon the process used, it can also result in a weld joint that hasporosity. Although in some welding applications an amount of porosity isacceptable, there are other applications where porosity can beproblematic. For example, when welding wheel structures that are usedfor pressurized tires the presence of porosity can result in a weldedwheel structure which fails to maintain pressure. To prevent this lossof pressure from occurring it is common to over-weld wheel structures toensure that the welded wheel structure is capable of maintainingpressure. However, this over-welding increases overall cost of thewelded wheel structure by increasing the amount of time needed to weldthe wheel and increases the material cost of the wheel, by requiringincreases amounts of filler metals used in the welding process.Therefore, it is desirable to provide a welding process which improvesthe efficiency and quality of welding wheel structures.

SUMMARY OF THE INVENTION

An exemplary embodiment of the present invention is a wheel structureand a method of welding a wheel stricture, where the method of weldingthe wheel structure includes positioning a first wheel section having afirst web portion adjacent to a second wheel section having a second webportion, such that each of the first and second web portions arecontacting each other. The method includes directing a laser beam to thefirst web portion, and autogenously welding the first web portion to thesecond web portion with a laser beam such that the laser beam passesthrough an entire thickness of the first web section and the laser beampenetrates at least a portion of a thickness of the second web portion.The autogenously welding creates a hermetically sealed weld joint arounda center the welded first and second wheel sections.

BRIEF DESCRIPTION OF DRAWINGS

The above and/or other aspects of the invention will be more apparent bydescribing in detail exemplary embodiments of the invention withreference to the accompanying drawings, in which:

FIG. 1 is a diagrammatical representation of a welded wheel inaccordance with an exemplary embodiment of the present invention;

FIG. 2 is a diagrammatical representation of another view of theexemplary wheel of FIG. 1;

FIG. 3 is a diagrammatical representation of an exemplary embodiment ofa welding system of the present invention; and

FIG. 4 is a diagrammatical representation of another view of theexemplary wheel of FIG. 1.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring now to the drawings wherein the showings are for the purposeof illustrating exemplary embodiments of the invention only and not forthe purpose of limiting the same, an apparatus and system used inpracticing the invention is shown in detail in FIGS. 1-4.

FIGS. 1 and 2 depict a wheel assembly 100 in accordance with anexemplary embodiment of the present invention. The wheel assembly 100contains a hub 101 and two wheel sections 103 and 105 which are to bewelded to each other. The hub 101 may or may not be a part of thecompleted wheel assembly 100 depending on the applications. As shown inFIG. 1, the wheel assembly 100 can have a tire 117 mounted to it. Thetire 117 and the sections 103/105 create a void or cavity 119 which canbe filled with air or gas under pressure and it is desirable for thesections 103 and 105 to be able to form an air tight and secure assemblyfor use. The shape and construction of the sections 103 and 105 shown inFIGS. 1 to 4 are intended to be exemplary and other embodiments of thepresent invention can utilize wheel sections having different shapes asdifferent applications require.

As shown in the Figures, each of the sections 103 and 105 contain a hubportion 108/110 which make contact with the hub 101 or other otherwiseadjacent to the centerline of the wheel assembly 100. The hub portions108/110 can have a flange extension, as shown, which extends along alength of the hub 101 or wheel centerline, or can have other shapes asneeded. Extending radially outward from the hub portions 108/110 are webportions 107/109 which are oriented perpendicular to the radialcenterline of the assembly 100. In the embodiment shown, the webportions 107/109 are of the same length, but in other embodiments thismay not be the case. Also, in the embodiment shown the web portions areshown as solid. However, in other exemplary embodiments it iscontemplated that holes can be made web portions 107/109 to reduce theoverall weight of the wheel assembly 100. The holes can be of any shapebut are usually made as circles, ovals or ellipses so as to avoidcreating locations of stress concentrations. The sizing and number ofholes should be determined to ensure that the structural integrity ofthe webs 107/109 are sufficient for their expected loading. The holesshould also be positioned radially inward from the weld bead 115—whichwill be discussed in more detail below.

Extending from the radially outward edges of the web portions 107/109are angled portions 111/113. The angled portions 111/113 diverge fromeach other respectively to define at least a portion of the pressurevoid 119. As shown in FIG. 1 the angled portions are angled between 0and 90 degrees from the cross-sectional centerline of the assembly 100.The angle to be chosen is based on the design and application of thewheel assembly 100. In some exemplary embodiments the angle can be 90degrees from the cross-sectional centerline. Extending from the radiallyoutward edge of the angled portions 111/113 are flange portions 112/114.The flange portions 112/114 can be utilized to hold a tire 117 or othersimilar component as needed. In the embodiment shown the flange portions112/114 are oriented parallel to the cross-sectional centerline of theassembly 100 as shown. However, in other embodiments this is notrequired as other angles can be utilized based on the application anddesign needs. In some exemplary embodiments, the flange portions 112/114are not needed as the angled portions 111/113 can themselves be utilizedto hold any structure or tire 117.

In the embodiments shown the wheel sections 103/105 are shown as anintegral component such that the hub, web, angled and flange portionsare all made of a single piece of material (usually metal). This can beformed in many different ways including pressing a flat material intothe desired shape. However, other exemplary embodiments are not limitedto the use of integral sections 103/105 as the sections 103/105 can bemade up of welded components.

The two wheel sections 103/105 are secured to each other by weldingtheir respective web portions 107/109, which make contact with eachother when the assembly 100 is assembled. As such, each of the webportions 107/109 have surfaces 116/118 which are parallel to each otherand made such that the surfaces 116/118 are flush with each other whenthe portions 103/105 are positioned adjacent to each other for assembly.It is not required that the surfaces 116/118 be flush with each otherfor the entire length of the web portions 107/108. However, thesesurfaces 116/118 should be flush with each other at least at the weldjoint 115.

In the shown exemplary embodiment, the weld joint 115 is a continuousweld joint 115 which forms a circular pattern around the assembly 100.The weld joint 115 is made by welding through one of the wheel sections103/105 and into the other of the wheel sections 103/105. In theembodiment shown in FIG. 1, the weld joint is welded through the section103 and into the section 105. However, as shown the weld joint 115 doesnot fully penetrate the thickness of the second of the sections (section105 in FIG. 1). In some embodiments, as discussed further below, thejoint 115 can fully penetrate the thickness of both sections 103/105 atthe weld.

Unlike prior welded wheel assemblies this weld joint 115 is not made viathe use of arc welding or with the use of filler metals. Rather the weldjoint 115 is made using a laser welding system in which no filler metalis used—this is commonly referred to as an autogenous weld. Filler metalis typically used to fill gaps during welding and/or to provideadditional material to a joint to form a fillet, or the like. However,because the surfaces 116/118 are flush with each other at the weld joint115 there is no gap to fill and therefore the weld joint 115 is madeentirely of the material of the web portions 107/109 and no filler metalis needed.

Furthermore, because the weld joint 115 is made to penetrate through theentire thickness of one section 103 and into at least some of the secondsection 105, the joint 115 creates a continuous seal around the entirewheel assembly 100. Because of this seal any pressure in the pressurezone 119 (like air pressure) will be unable to pass between the portions103/105 and escape at the hub 101—which is a problem with arc weldedwheels. Thus, this weld joint 115 creates a hermetic weld joint.Therefore, embodiments of the present invention can create a weldedwheel assembly 100 having a weld made with no filler material whichprovides the needed structural integrity and the needed air tight sealfor pressurized wheel applications. With embodiments of the presentinvention, a significant amount of filler material and welding isavoided, as it is often needed to weld the sections 103/105 to the hub101—with filler metal—to provide the required air tight seal.

As shown in FIG. 2, the weld joint 115 has a circular pattern along aradius from the center of the assembly 100. However, embodiments of thepresent invention are not limited in this regard. For example, it iscontemplated that the weld joint 115 can have a zig-zag or undulatingpattern along a radius from the center of the assembly 100. Such apattern would increase the overall length of the weld joint 115 toprovide added structural integrity. However, the weld joint 115 shouldbe continuous so as to provide the requisite hermetic seal between thesections 103/105, if the wheel is to be used in a pressurizedapplication. It is noted that to the extent holes are placed in the webs107/109 to reduce the weight of the assembly (as discussed above) theweld joint 115 should be placed radially outward from the holes toprovide the needed air tight seal—in pressurized applications. Ofcourse, many different types of patterns can be used for the weldingoperation.

It is further noted that although a single weld joint 115 is shown inthe figures, the present invention is not limited in this regard.Specifically, additional weld joints can be used to increase thestrength of the wheel assembly 100. For example, another weld joint canbe positioned radially inward or outward from the weld joint 115.Further, any additional joint does not have to be continuous but can bean intermittent or spot weld joint. As long as one weld joint (115) iscontinuous, any additional weld joint will not have to be continuous toprovide the requisite air tight seal. Of course, it can be continuous aswell—if needed.

FIG. 3 depicts an exemplary welding system 300 for welding the assembly100 described above. As discussed above, the weld joint 115 is createdusing a laser welding system with no filler metal. The system 300includes a laser power supply 301 which supplies power to a laser 305.The laser 305 can be any known type of laser which is capable of laserwelding, including but not limited to carbon dioxide, Nd:YAG, Yb-disk,YB-fiber, fiber delivered or direct diode laser systems. Further, whitelight or quartz laser type systems can be used if they have sufficientenergy. Other embodiments of the system may employ electron beam energy.Exemplary lasers should have power capabilities in the range of 1 to 20kW. Higher power lasers can be utilized, but can become very costly. Inthe embodiment shown, the laser 305 is emitting a single beam 307 toweld the joint 115. However, a multiple beam configuration can also beemployed if desired. A multiple beam configuration can use multiplelasers 305 and/or beam splitters with a single laser 305 as desired. Insuch an embodiment the separate beams can be used to make separateportions of the same continuous weld, or can be positioned adjacent toeach other to make a wider weld joint.

The laser 305 emits a beam 307 having a sufficient energy and shape tofully penetrate or keyhole the entire thickness of the web portion107/109 of one of the wheel sections 103/105 and at least some of thethickness of the web portion 107/109 of the other of the wheel sections103/105. This will be discussed further below.

The system 300 also includes a system controller 303 which monitorsand/or controls the power supply 301 and/or the laser 307 to produce asufficient weld. Additionally, in the embodiment shown the controller303 also controls a motor 311 which is coupled to a platen 309 whichrotates during welding. In the embodiment shown, the platen 309 isrotated while the laser 305 and beam 307 remain stationary to completethe weld. Of course, in other exemplary embodiments the laser 305 can bemoved to create the joint 115. In further embodiments, both the wheel100 and the laser 305 can be moved to create the weld, or the laser 305can remain stationary while the beam 307 is moved using optics of thelaser 305. Embodiments of the present invention are not limited in thisregard, as other means of creating the weld can be used. For example,other configurations can use mirrors or optics external to the laseroptics which move and translate to create the desired weld pattern.

It is noted that although the controller 303, power supply 301, laser305, motor 311 and platen 309 are shown as separate components in FIG.3, this is done for clarity. It is contemplated that at least some orall of these components can be made into an integral unit or assembly toperform the welding operation. It is not required that these componentsare separate physical structures.

Turning now to FIG. 4, a more detailed view of the joint 115 is shown.As shown, the web 107 has a length W and the center of the weld joint115 is positioned a distance L from the outer radial edge of the web107. In most embodiments this distance should be relatively small sothat the joint 115 is close to the angled portions 111/113. This willaid in minimizing the moment forces on the webs 107/109 when theassembly 100 is in use. In exemplary embodiments of the presentinvention, the distance L should be based on the thickness of the webmaterial and the design loads on the wheel in the area of the weld 115.If the web is of sufficient thickness and stiffness the distance L canapproach 0% of the length W. However, in other embodiments the distanceL is in the range of 10 to 80% of the web length W.

Furthermore, the web 109 has a thickness T and the weld joint 115penetrates the web 109 by a distance D. In exemplary embodiments thedistance D is less than the thickness T. In some exemplary embodiments,the distance D is in the range of 5 to 100% of the thickness T, as longas the distance L results in a structurally sound weld. In otherembodiments the distance is in the range of 20 to 75%. Of course, otherdepths can be employed as needed. In fact, in some exemplary embodimentsthe joint 115 will keyhole through both web portions 107/109. Thesewelds will penetrate 100% of the thickness T and provide a “witnessmark” on the back of the web to allow for inspection of the weldjoint—to ensure sufficient penetration. However, to the extent that bothweb portions 107/109 are fully keyholed the back bead of the joint 115should be controlled carefully so that no significant amount of weldmetal sags below the bottom web portion 109 as this could create acavity in the upper surface of the weld joint (as no filler metal isemployed).

In some exemplary embodiments the depth of the weld joint 115 in thelower portion 109 can vary along the length of the weld. For example, itmay not be structurally necessary for the weld joint to have a constantdepth in the lower web portion 109. Therefore, in some exemplaryembodiments portions of the weld joint 115 can be at a first depth andother portions of the joint 115 can have a second depth, which isshallower than the first depth. For example, the first depth D can be goup to 100% of the thickness T of the web 109 and the second depth can bein the range of 5 to 50% of the thickness T, where the second depth isless than the first depth. Any change or depth differential can be madeas long as at least one weld results in a hermetic seal and the weldjoint(s) meet the desired mechanical strengths. The length of thedifferent depth sections can vary as well depending on the strengthrequirements of the weld joint 115. For example, the first depth can bewelded for 2 inches while the shallower depth can then be welded for 5inches and then return to the first depth for 2 inches, etc. This allowsfor the optimization of the weld joint 115 in the wheel. Thisoscillating depth can be created by changing the energy density of thebeam 307 during the welding operation. Such an embodiment can speed thewelding operation and conserve welding energy. This variation in welddepth can also be achieved by changing the shape of the beam 307, theenergy density of the beam, and/or the speed of the welding process.

The cross-sectional width of the weld joint 115 at the meeting of thesurfaces 116/118 should be sufficient to provide the needed structuralintegrity for the weld. Embodiments of the present invention are notlimited by the overall cross-sectional shape of the weld joint, exceptthat the point 115 should have the required structural integrity. Toincrease the width of the joint 115 (if needed) a multi-beam laserwelding process can be used. In exemplary embodiments, the weld joint115 at the meeting of the web portions 107/109 has a width Z. The widthZ should be sufficient to hermetically seal the wheel 100 as well asprovide whatever strength is needed. In some exemplary embodiments ofthe present invention the width Z is in the range of 10 to 100% of thethickness T. In some exemplary embodiments, the weld joint 115 may notbe needed to provide strength to the wheel. As such, a thinner weldjoint 115 can be employed which is used to primarily hermetically sealthe wheel. For example, in such embodiments the weld joint can have awidth Z in the range of 5 to 50% of T. In some exemplary embodiments,the width Z is not constant for the entire weld. For example, it may notbe necessary to have the entire length of the weld joint 115 at aconstant thickness because of strength requirements. In suchembodiments, some portions of the joint 115 can have a first thicknessZ, while other portions have a second thickness Z which is less then thefirst section. In such embodiments the first sections can provide thebulk of the strength of the joint 115 while the thinner sections provideless strength but continue the hermetic seal. Such embodiments allow forthe conservation of energy during the welding process. In some exemplaryembodiments, multiple beams can be used to vary the width of the weldjoint 115 during welding.

Embodiments of the present invention allow for the creation ofhermetically sealed wheel assemblies 100 which have been weldedautogenously in less than half of the time as prior art wheels, withsignificantly less cost and less product scrapping due to porosity fromarc welding.

Of course, it should be noted that the sections 103/105 can have otherweld joints than those described herein as needed or desired. Forexample, in some other exemplary embodiments the hub portions 108/110can be welded to the hub 101 for added strength. Alternatively the hubportions 108/110 can be autogenously welded to the hub in lieu ofwelding through the web portions 107/109. Depending on the constructionof the wheel 100 the autogenous weld joint can be placed anywhere asneeded so that the desired strength and hermetic seal is achieved.Further, the sections 103/105 can be welded to each other at the contactpoint between the sections (the seam where they contact each other)inside the void 119. These welds can be laser welds as described herein.Of course, there can be multiple welds on the wheel assembly 100 asdesired, where at least one weld is autogenous. Depending on the fit ofthe sections 103/105, it may be necessary in some parts of the wheel touse a weld with filler material to fill in gaps. This can be done withany known welding method which uses filler material.

While the invention has been particularly shown and described withreference to exemplary embodiments thereof, the invention is not limitedto these embodiments. It will be understood by those of ordinary skillin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the invention as definedby the following claims.

What is claimed is:
 1. A method of welding a wheel structure,comprising: positioning a first wheel section having a first web portionadjacent to a second wheel section having a second web portion, suchthat each of said first and second web portions are contacting eachother, and each of said first and second web portions are of the samelength; directing a laser beam to said first web portion; andautogenously welding said first web portion to said second web portionwith a laser beam such that said laser beam passes through an entirethickness of said first web section and said laser beam penetrates 5 to100% of said thickness of said second web portion and a penetrationdepth of said laser beam in said second web section varies along alength of a path of said laser beam; wherein said autogenously weldingcreates a continuous hermetically sealed weld joint around a center ofthe welded first and second wheel sections, and wherein said first webportion has a web length between a hub portion positioned radiallyinward from said first web portion and an angled portion positionedradially outward from said first web portion, and said weld joint ispositioned on the first web portion 10 to 80% of the web length inwardfrom said angled portion.
 2. The method of claim 1, wherein at leastsome of said weld joint penetrates 20 to 75% of said thickness of saidsecond web portion.
 3. The method of claim 1, wherein said weld joint iswelded in a pattern having a nonconstant radial distance from saidcenter.
 4. The method of claim 1, wherein said weld joint has a firstportion with a first depth of up to 100% of the thickness of said secondweb portion and a second depth of 5 to 50% of the thickness of saidsecond web portion, where said second depth is less than said firstdepth.
 5. The method of claim 1, wherein said weld joint has a firstportion with a first depth of 20 to 50% of the thickness of said secondweb portion and a second depth of 5 to 50% of the thickness of saidsecond web portion, where said second depth is less than said firstdepth.
 6. The method of claim 1, wherein said weld joint has a width inthe range of 10 to 100% of the thickness of said second web portion atthe point at which said first and second web portions contact eachother.
 7. The method of claim 1, wherein a width of said weld joint atthe point at which said first and second web portions contact each othervaries between a first width and a second width, where said first widthis in the range of 10 to 100% of the thickness of said second webportion and said second width is in the range of 5 to 50% of thethickness of said second web portion, and wherein said second width isless than said first width.
 8. The method of claim 1, wherein at leastone of said first and second web portions has cavities through an entirethickness of said first or second web portion and said weld joint ispositioned radially outward from said cavities.
 9. A welded wheelstructure, comprising: a first wheel section having a first web portion;a second wheel section having a second web portion, where each of saidfirst and second web portions are contacting each other, and each ofsaid first and second web portions have the same length; and acontinuous hermetically sealed weld joint which welds said first webportion to said second web portion, such that said weld joint passesthrough an entire thickness of said first web portion and has a depth insaid second web portion of 5 to 100% of a thickness of said second webportion, and wherein a depth of said weld joint in said second webportion varies along a length of said weld joint; wherein said weldjoint is positioned radially around a center of said welded first andsecond sections, wherein said weld joint is an autogenous weld joint,and wherein said first web portion has a web length between a hubportion positioned radially inward from said first web portion and anangled portion positioned radially outward from said first web portion,and said weld joint is positioned on the first web portion 10 to 80% ofthe web length inward from said angled portion.
 10. The welded wheelstructure of claim 9, wherein at least a portion of said weld jointpenetrates 20 to 75% of said thickness of said second web portion. 11.The welded wheel structure of claim 9, wherein said weld joint is weldedin a pattern having a nonconstant radial distance from said center. 12.The welded wheel structure of claim 9, wherein said weld joint has afirst portion with a first depth of up to 100% of the thickness of saidsecond web portion and a second depth of 5 to 50% of the thickness ofsaid second web portion, wherein said second depth is less than saidfirst depth.
 13. The welded wheel structure of claim 9, wherein saidweld joint has a first portion with a first depth of 20 to 50% of thethickness of said second web portion and a second depth of 5 to 50% ofthe thickness of said second web portion, wherein said second depth isless than said first depth.
 14. The welded wheel structure of claim 9,wherein said weld joint has a width in the range of 10 to 100% of thethickness of said second web portion at the point at which said firstand second web portions contact each other.
 15. The welded wheelstructure of claim 9, wherein a width of said weld joint at the point atwhich said first and second web portions contact each other variesbetween a first width and a second width, where said first width is inthe range of 10 to 100% of the thickness of said second web portion andsaid second width is in the range of 5 to 50% of the thickness of saidsecond web portion, and wherein said second width is less than saidfirst width.
 16. The welded wheel structure of claim 9, wherein at leastone of said first and second web portions has cavities through an entirethickness of said first or second web portion and said weld joint ispositioned radially outward from said cavities.
 17. A welded wheelstructure, comprising: a first wheel section having a first web portion;a second wheel section having a second web portion, where each of saidfirst and second web portions are contacting each other; and acontinuous hermetically sealed weld joint which welds said first webportion to said second web portion, such that said weld joint passesthrough an entire thickness of said first web portion and has a depth insaid second web portion of 5 to 100% of a thickness of said second webportion, and wherein a depth of said weld joint in said second webportion varies along a length of said weld joint; wherein said weldjoint is positioned radially around a center of said welded first andsecond sections, wherein said weld joint is an autogenous weld joint,wherein said first web portion has a web length between a hub portionpositioned radially inward from said first web portion and an angledportion positioned radially outward from said first web portion, andsaid weld joint is positioned on the first web portion 10 to 80% of theweb length inward from said angled portion.